1. Field of the Invention
The field of the invention is that of the transmission and broadcasting of digital signals, in particular in the presence of transmission noise.
The invention relates to a method for ordering the users at a receiver comprising an equalizer and a decoder before carrying out the signal processing.
The invention applies in a CDMA (code division multiple access) context with channel coding.
It applies in particular to third generation mobile radio systems.
2. Description of Related Art
In digital transmission, a receiver can be viewed as a succession of several elementary functions each performing a specific process such as filtering, demodulating, equalizing, decoding, etc.
The CDMA technique is a multiple access technique which will form the basis of third-generation mobile radio systems.
The technique is based on the spread spectrum principle in which transmission takes place at a much higher bit rate than necessary for each user, by multiplying the useful symbols by sequences of high bit rate symbols, called “spreading sequences”.
All the transmissions are then performed at the same frequency and at the same times, separation between the users being obtained by different spreading sequences.
The prior art describes receivers which make use of successive interference subtractions so as to order the users according to specific criteria.
For example, one method consists in classifying the users according only to the power associated with a user.